Coking of coal



M 2.4, 3923- Ml-62,576

S. R ILL-INGW'ORTH COKlNG OF COAL Filed Aug. 29 1921 Patented July 243,,110233.

UNHTEE STATES PATENT EHEWART ROY ILLINGWOETH, 0F BRYNFEDWEN, ENGLAND,ASSKGHOE T0 ILMIUG WORTH CAWONIZATION COMPANY, LIMITED, 0F MANCHESTEE J,ENGLAND.

0031376 035' COAL.

Application filed August 29,10fil.

To all whom it may concern:

Be it known that I, STEWART Ror TLLINowon'rn, a subject of the King ofGreat Britain, residing at Brynfedwen, Radyr, Glamorganshire, England,have invented new and useful Improvements in the Coking of Goal, ofwhich the following is a speci cation.

This'invention relates to the production of various types of coke and isan improvement on the process described in the specification of ourformer application No.

448,871, now Patent No. 1,422,269, July 11, 1922.

The majority of coals, particularly the highly bituminous coals whencarbonized at low temperatures namely temperatures up to 600 C. givesoft porous products, which readily disintegrate with handling, anddurin transport. In order to overcome this di culty various means havebeen suggested, in the main these methods have depended on mechanicalcompression of the charge, either by virtue of some special type offurnace, or at some stage after discharge therefrom, the addition ofpitch, binders and the briquetting of the mass carbonized at lowtemperatures, and subsequent carbonization of this mass at highertemperatures has been advocated.

By the present invention I am able without the use of compression, theaddition of binders or other means to produce at low temperatures densehard fuel concurrent with the production of excellent yields of byeproducts such as oils and ammonia. This dense hard fuel has all thephysical characteristics of metallurgical coke, and can be convertedinto the latter by heating the product formed at low temperatures (sayunder 600 C.) to higher temperatures up to about 900 C.1000 C.

My process comprises the following opera tions:

Firstly preheating the .coal'to obtain a productof the nature requiredfor the second operation.

Secondly crushing if necessary this product and carbonizing the productat temperatures not exceeding 600 C. but preferably not exceeding 500 C.This opera tion is designated as the formation of coke Qerial No.400,763.

structure since in this operation the resinic matter in the residue iswholly destroyed as such, and when this has taken place the mass cannotagain be brought into a plastic state by heat, that is the texture ofthe product cannot undergo appreciable change. The product at this stageis smokeless fuel:

Thirdly, coking of the product of the second operation at temperaturesabove 600 C. If true coke (i. e. a coke of low volatile content). isdesired, the product from the second operation is passed as soon as allthe bye-products have been evolved to an oven maintained at anytemperature above 600 C. in order to eliminate the desired amount ofvolatile matter from the smokeless fuel; at 900 C. the product loses allvolatile matter.

The preheating operation depends on the nature of the coal, firstly thecoal must contain the requisite quantity of resinic matter to cement thecoal into coke. Tn the specification of in previous patent applicationNo. 448,871 have shown that the resinic matter in coal is of varyingdegrees of sta bility, and that associated with it are vari- Qus typesof non-cementing material ({5 cellulosic, etc.) which is also of varyingdegrees of stability. Now by the employment of suitable temperatures itis possible to eliminate from a coal certain portions of theseconstituents and to leave a residue which contains a more homogenoustype of resinic matter (i. e. the resinic matter in the residue isdecomposed between short limits of temperature) further this resinicmatter is associated with a small amount of other substancesdecomposable at the same temper ature as the resinic. Therefore when theformation of coke structure subsequently takes place the plastic mass isunder the influence of the least possible distending influence, that isto say, the least possible quantity of volatile matter is evolved atthis stage.

The following examples make this clear 2-- Example L-A coal gave 40%volatile mat ter at 900 C. on the ash tree and dry basis and contained12.6 resinic matter when extracted with boiling phenol, and 26% {5cellulosic matter and evolved 21% maximum volatile matter at 350 C, Thewhole of its and 7.26%

resinic matter such as decomposed at 400 The virgin coal ve a softsintered semlcoke on direct cai zonization at 500 C. and a soft sintercoke when carbonized direct at This coal was preheated as follows 1 Itwas heated in thin lagers (1") mechanically agitated at 350 for 1%hours. The coal lost 10% by weight. The product contained 8.6% ofresinic matter, and gave less than 0.5% matter volatile at 300 C.volatile matter at 350 C. On crushing the cooled product andsubsequently submitting it to the process of coke formation at 480 C. adense hard smokeless fuel (with 10.3% volatile at 900 C.) was obtained,gallons per ton of oil being obtained. The coke formation took place inlayers- 3" thick, and this stage was com-\ plete in 2?; hours.Metallurgical coke was made as follows: The operation up to theformation of coke structure was conducted as in the revious case, butinstead of discharging t e smokeless fuel from the oven, it waspushedinto an oven at 900 C. for 1% hours, the coke resulting was of a densehard nature and had only 0.6% volatile at 900 C. The yield of oil wasagain 25 gallons and the equivalent of 24 lbs. of ammonium sulphate wasproduced per ton.

Example 2.A coal of 28.6% volatile at I 900 C. gave 15% (ash free drybasis) total volatile'at 400 0.; it contained 21% resinic matter and 22%(5 cellulosic. The resinic matter was wholly destroyed at 450 C. Thecoal was preheated for 1 hour at 300 C., then for 2} hours at 420 C. Theresult-in residue contained 9% resinic matter. t gave no volatile at 350(3., 6% total volatile 1st 400 C. and contained only 1.6% 6 cellu- Theroduct was in the form of a very soft co e; this was crushed and theformation of: coke structure performed at 600 C. A dense hard smokelessfuel containing 4.5% volatile matterat 900 C. resulted. The yield of oilwas 24 llons.

It is to be noted t at I have shown that in the virgin coals cokestructure is formed at temperatures varying from 350 up to 450 accordingto thenature of the coal; in the case of t e highl, bituminous coals thetemperature deal; he lower; limits. Now.;.i-;.i-; these coals arecarbonized at low tempera tures and-the resulting residue heated tohigher temperatures the: coke structure initially formed persists.Usually any coke structure .formed in the preheating is broken deWn' 'bygrinding prior to the process of the formation of coke structure atabout 500-600C.

It.-.-has been found that coke is formed at temperatures varying from350 to 500 C.

according to the nature of the coal and furthe'rcertain coals of a highvolatile connot exceedin tent at 900 C. which do not coke under presentpractice can be coked at temperatures from 350-500 C. rovided that theseare of such nature that t ey can be suitably preheated so as to leave56% resinic matter in the preheated coal. And it has been found thatwhen the coke structure is formed this structure will remain throughoutthe mass of coke independently of the temperatures the coke may besubsequently submitted to. The resinlc matter in coal which has beenmaintainedabove 500 C. for a short period will be decomposed and nofurther coking eifect can be produced as the resinic matter is the cokeproducing ingredient in the coal so long as the amount of resinic matteris above 5% and all resinic matter is decomposed at 450 to 500 C.Resinic matteris of different degrees of stability and associated withit is non-coke producing matter which decomposes below 500 C., theresult being that if coal is coked without preheating at 400 to 500 C.the resinic matter is only slowly decomposed and the non-cokingmattercauses the lastic mass to distend and a porous coke is produced. Thisdistention is more marked with coal containing large quantities ofvolatile matter. If however-the coal is suitably preheated the producton coking does not expand but in many cases contracts.

According to the present invention as above state coalis preheated asdescribed in our former specification and is coked in an oven in whichthe temperature does not exceed, 600 C. but which preferably does notexceed 500 C. to form the coke structure: The roduct may afterwards bebeated to a higlier temperature.

It is common knowledge that the bye products obtained from thecarbonization of coal vary in nature and amount with the temperatureemployed. When high temperatures (say 900 C.) are used, the earliertermed products are decomposed and undergg change from open chaincompounds and lly saturated c ain compounds tosubstances of the aromaticseries and concurrent with this change the volume is decreased. Thecritical range of temperatures for this change is from 500 C. to 600 C.and consequently ifbye products are required of a quality suitable-forrefining into substitutes for natural petroleum products, I coke thepreheated coal at a temperature 500 C.; if however it be desired to pruce bye products for use as a fuel or in'an unrefined state atemperature above 500 C. but below 600 C. may be used. The effect of thehigher temperature on the nature of the'coke is to cause'slightlygreater porosity therein due to the steeper temperature gradient in themass undergoing carbonization; this fact can be minimized by preheatingthe coal 'to the greatest extent possible i. e. to leave therein theminimum uantity of resinic substance necessary for t e production ofcoke.

Further the valuable bye products arise in the main from the substancesin coal decomposed below 500 (3., conse uentl in carbonizing coal theportion sta lo a ve this temperature is of little value by comparison,for the production of bye products. I therefore preferably carry out theformation of coke structure at a maximum temperature of 500 (3., but insome cases T may use a higher temperature not exceeding 600 C.

' In the case of the preheated coals whose non-coke producingconstituents are decomposed below 500 C. it is found that the nearer thetemperature at which the coking is conducted to the temperature ofdecomposition of the resinic matter therein, the more dense thestructure of the coke. Thus if coals are used in which the major portionof the resinic matters decompose around 400 C. it is preferable in orderto obtain a dense coke to coke the preheated coal nearer to i50 C. than500 C.

For example the coal is heated for from 3 to 4 hours at 400 C. or for ashorter period at a higher temperature, ea 450 C.- The product after.crushin (i necessary) is placed in an oven in w ich the tem rature 18about 500 C. and a coke containing 10% of volatile matter nd of a densehard nature is obtained. lit this coke is heated for two hours at 000 C.volatile matter will be driven 05 leaving 5% of volatile matter, and ifheated for 1%- hours at 700 C. the coke will contain 2% to 3% volatilematter, or

if heated for. 1 hour at 900 C. practically no volatile matter will beleft in the coke. Thus the de e and time to which the product is heatafter the formation of the coke structure at about 500 C. depends uponthe product re uired. The coke may be obtained by using a highertemperature than 500 C. but 500 (1 is the maximum temperature for theformation oil coke structure and gives a higher yield of liquid byeproducts, a denser structure of coke which contains around 10% volatileand can be burnt under normal conditions of combustion.

The coal maybe preheated in stages as described in my formerspecification. F or example coal containing 28.6% volatile matter at 900C. was heated for a period at 300 C. and then the temperature was slowlyraised to 420 (3. for another period, and the product was shot into anoven having a temperature otfrom 480 to 500 (3., the re sult being thata dense hard coke was obtained; this can be'used as a fuel. This cokecontained 10.3% volatile matter and was heated to a temperature of 900C. A

dense hard coke of the original structure was-formed containing 1.2%volatile matter.

The drawin show diagrammatically an apparatus which ma be umd incarrying out this invention. higure 1 is a plan of one end of an ovenand Figure 2 is a side elevation of part of one of the sides of theoven.

The oven is of ellipsoid form having guides (1 upon which run the wheelsb b on one side and the wheels 0 on the other side of each of a numberof truck frames (1 coupled together by links 6. To the frames d arepivoted trays fiend the trays are provided with jockey w eels g. On theframes (1 and the links 6 are ratchet teeth It adapted to engage with atoothed wheel 2' on the same axis j as another wheel is which wheel kmay be driven in any desired manner. The ratchet It comes below thewheel 2" whereby the truck is driven and the whole system of trucksmoves round the oven. At one side of the oven is a feed hopper m havinga measuring device n so that when a truck arrives beneath the hopper mthe requisite amount of material is delivered on to the tray f. When thetrucks have completed a'circuit of the oven they deliver their contentsinto a chute 0 which may lead to a cooling chamber or to a furnace to befurther heated. The trucks may be operated intermediately orcontinuously by varying the drive of the wheel 7:.

By the use of such an apparatus thin layers of the material may beheated continuously so that a more uniform heatin and a shortening ofthe time required is o tained than when the material is heated in largemasses. Difierent parts of the ovens may be heated to diderenttemperatures so that the mrials may be heated in stages.

What ll claim is 1. The process of coking coal in which the coal issubmitted to heat out of contact with air in order to destroythe'non-coke producing substances in the coal but tn leave 5% by weightof the resinic substances in the product in order to prevent expansionof the coke during the coking process and then colting the preheatedcoal at a temperature which does not exceed 500 C.

2. The process of coking coal in which the coal is heated for definiteperiods at increesa ing temperatures out of contact with air in order todestroy the non-coke producing substances in the coal but tofleave 5% byweight of the resinic substances in the roduct in order to preventexpansion or the coke during the coking process. and than coking thepreheated coal at a temperature which does not exceed 500 C.

3. The process 0t coking coal in which the coal is submitted to atemperature below 400 (3. out of contact with air in order to destroythe non-coke producing substances in the cool but to leave 5% by weightoi the regime ubstances in the product in order to then cokin preventexpansion of the coke during1 the coking process and then coking the preeated coal ata temperature which does not exceed 500 C.

4. The process of coking coal in which the coal is heated for definiteperiods at increasing temperatureslaelow 400 C. out of contact with airin order to destroy the noncoke producing substances in the coal but toleave 5% by weight of the resinic substances in the product in order toprevent expansion of the coke during the coking process and then cokingthe preheated coal at a temperature which does not exceed 500 C.

5. The process of coking coal in which the coal is submitted to heat outof contact with air in order to destroy the non-coke producingsubstances in the coal but to leave 5%Ob1y weight of the resinicsubstances in the r uct in order to prevent expansion 0 the coke duringthe coking process, crushing the product and then coking the crushedproduct at a temperature which does not exceed 500 C;

6. The process of coking coal in which the coal is submitted to atemperature below 400 C. out of contact with air in order to destroy thenon-coke producing substances in the coalbut to leave 5% b weight of theresinic substances in the pr not in order to prevent expansion of thecoke during the coking process, crush the product and the crush productat-a temperature w ich does not exceed 500 C.

7. The process of coking coal in which the coal is submitted to heat outof contact with air in order to destroy the non-coke producingsubstances in the coal but to leave 5% by weight of the resinicsubstances in the product in order to prevent expansion of the cokeduring the co ing process, then coking the preheated coal at atemperature which does not exceed 500 C. and then heating the product toa. higher temperature to drive oil the volatile matter to obtain aproduct easily removed from the retort.

8. The rocess of cokin coal in which the coal is heated for de niteperiods at increasing temperatures out of contact with air' in order todestro the non-coke producing substances in t e coal but to leave 5% byweight of the resinic substances in the product in order to preventexpansion of the coke during the coking process, then cokingthe'preheated coal at a temperature which does not exceed 500 C. andthen heating the product to a higher temperature to drive 0 producteasily removed from the retort.

9. The process of coking coal in which the coal is submitted toat-temperature below 400 C. out of contact with air in order to destroythe non-coke producing substances in the coal but to leave 5% by weightof the resinic substances in the roduct in order the volatile matter toobtain a' to prevent expansion of the coke during the cokin process,then coking the preheated coa at a tem erature which does not exceed 600C. and tlien heating the product to a higher temperature to drive oilthe 'volatile matter to obtain a product easily removed from the retort.

10. The process of coking coal in which the coal is heated for definiteperiods at increasing temperatures below 400 C. out of contact with airin order to destroy the noncoke producing substances in the coal but toleave 5% by weight of the resinic substances in the product in order toprevent expansion of the coke during the coking process, then coking thepreheated coal at a 4 temperature which does not exceed 600 C. andheating the product to a higher temperature to drive off the volatilematter to obtain a product easily removed from the retort.

11. The process of coking coal in which the coal is submitted to beatout of contact with air in order to destroy the non-coke producingsubstances in the coal but to leave 5% by-weight of the resinicsubstances in the product in order to prevent expansion of the cokeduring the cokin process, crushing the product, then coking t e crushedproduct at a tem rature which does not exceed 600 C. an then heating theproduct to a higher tem erature to drive of! the volatile matter to oain a product easily removed from the retort.

l 12, The process of coking coal in which the coal" is submitted to atemperature below 400-G. out of contact with air in order to destroy thenon-coke producing substances in the coal but to leave 5% by weight ofthe resinic substances in the product, crushing the product, then cokingthe crushed product at a temperature which does not exceed 600 C. and ten heating the product to a higher temperature to drive ofi the volatilematter to o tain a product easily removed from the retort.

13. The process of coking coal in which the coal is submitted to heatout of contact with air in order to destroy the noncoke producingsubstances in the coal but to leave 5% by weight of the resinicsubstances in the product in order to prevent expansion of the cokeduring the coki process, and then coking the preheated coa at atemperature which does not exceed 600 degrees C. to obtain a producteasily re moved from the retort.

14. The process of coki coal in which the coal is heated for 'de niteperiods at increasing temperatures out of contact with an in order todestroy the non-coke producmg substances in the coal but to leave 5% byweight of the resinic substances in the product in order to preventexpansion of the coke during the coking proces, and then meee're orderto prevent expansion of the coke during the ooki proce$, crushing theproduct and then coking the crushed product et a tempereture whlch doesnot exceed 600 degrees C. to obtain a from the retort.

In testimony that I cleirn the foregoing es m invention 1 heve signed myneme this third dey of Au st,' 1921.

STEWART ROY ILLINGWURTH.

product easily removed to

